Hi Sac users,
I have OBS record that follows the right-handed
system in which H2 component is 90 degree counter-clockwise of H1.
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation
correction of 80 degrees has to be made. For this, logically -80/360-80
degree should be implemented to rotate it back to North-South. Would +80
degree be fine?
2. What exactly sac does on applying reverse at the end of rotate command?
Thanks in advance.
Regards
Sanjay
I have OBS record that follows the right-handed
system in which H2 component is 90 degree counter-clockwise of H1.
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation
correction of 80 degrees has to be made. For this, logically -80/360-80
degree should be implemented to rotate it back to North-South. Would +80
degree be fine?
2. What exactly sac does on applying reverse at the end of rotate command?
Thanks in advance.
Regards
Sanjay
-
Hello Sanjay,
Based on the SAC documentation, your description of components, and
assuming that your
orientation correction is clockwise from north (+80?, how did you estimate
this?), it seems that "rotate to -80 reverse" is correct.
"Reverse" indicates that H2 is pointing north and H1 is pointing east: the
second component is lagging the first by 90°. Think of it as the reverse
convention as, usually, H1 and H2 are pointing north and east respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS) <
sac-help-bounce<at>lists.ds.iris.edu> wrote:
Hi Sac users,
--
I have OBS record that follows the right-handed
system in which H2 component is 90 degree counter-clockwise of H1.
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation
correction of 80 degrees has to be made. For this, logically -80/360-80
degree should be implemented to rotate it back to North-South. Would +80
degree be fine?
2. What exactly sac does on applying reverse at the end of rotate command?
Thanks in advance.
Regards
Sanjay
Januka Attanayake
Research Fellow | Earthquake Seismology
Homepage: *https://sites.google.com/site/janukaattanayake
https://sites.google.com/site/janukaattanayake*
School of Earth Sciences | McCoy Bldg. 200
University of Melbourne | Parkville 3010 VIC
Australia
-
Sanjay
To convert right-handed system into left-haded, you will need to flip the vertical component.
For a high-handed system, positive vertical points down.
-John
On Oct 27, 2020, at 5:11 AM, Geo . (via IRIS) <sac-help-bounce<at>lists.ds.iris.edu> wrote:
[This email originated from outside of OSU. Use caution with links and attachments.]
Hello Sanjay,
Based on the SAC documentation, your description of components, and assuming that your
orientation correction is clockwise from north (+80?, how did you estimate this?), it seems that "rotate to -80 reverse" is correct.
"Reverse" indicates that H2 is pointing north and H1 is pointing east: the second component is lagging the first by 90°. Think of it as the reverse convention as, usually, H1 and H2 are pointing north and east respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS) <sac-help-bounce<at>lists.ds.iris.edu> wrote:
Hi Sac users,
I have OBS record that follows the right-handed system in which H2 component is 90 degree counter-clockwise of H1.
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation correction of 80 degrees has to be made. For this, logically -80/360-80 degree should be implemented to rotate it back to North-South. Would +80 degree be fine?
2. What exactly sac does on applying reverse at the end of rotate command?
Thanks in advance.
Regards
Sanjay
--
Januka Attanayake
Research Fellow | Earthquake Seismology
Homepage: https://sites.google.com/site/janukaattanayake
School of Earth Sciences | McCoy Bldg. 200
University of Melbourne | Parkville 3010 VIC
Australia
----------------------
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Topic home: http://ds.iris.edu/message-center/topic/sac-help/ | Unsubscribe: sac-help-unsubscribe<at>lists.ds.iris.edu
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-
Hi John,
I never thought about it, but logically it seems correct.
It means that in order to flip, I need to rotate the vertical component to
180 degrees.
Thanks,
Sanjay
On Wed, Oct 28, 2020 at 1:31 AM Nabelek, John (via IRIS) <
sac-help-bounce<at>lists.ds.iris.edu> wrote:
Sanjay
--
To convert right-handed system into left-haded, you will need to flip the
vertical component.
For a high-handed system, positive vertical points down.
-John
On Oct 27, 2020, at 5:11 AM, Geo . (via IRIS) <
sac-help-bounce<at>lists.ds.iris.edu> wrote:
[This email originated from outside of OSU. Use caution with links and
attachments.]
Hello Sanjay,
assuming that your
Based on the SAC documentation, your description of components, and
orientation correction is clockwise from north (+80?, how did you
estimate this?), it seems that "rotate to -80 reverse" is correct.
"Reverse" indicates that H2 is pointing north and H1 is pointing east:
the second component is lagging the first by 90°. Think of it as the
reverse convention as, usually, H1 and H2 are pointing north and east
respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
sac-help-bounce<at>lists.ds.iris.edu> wrote:
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS) <
Hi Sac users,
system in which H2 component is 90 degree counter-clockwise of H1.
I have OBS record that follows the right-handed
Horizontal component data file are as following:
correction of 80 degrees has to be made. For this, logically -80/360-80
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation
degree should be implemented to rotate it back to North-South. Would +80
degree be fine?
2. What exactly sac does on applying reverse at the end of rotate
command?
Thanks in advance.
Unsubscribe: sac-help-unsubscribe<at>lists.ds.iris.edu
Regards
Sanjay
--
Januka Attanayake
Research Fellow | Earthquake Seismology
Homepage: https://sites.google.com/site/janukaattanayake
School of Earth Sciences | McCoy Bldg. 200
University of Melbourne | Parkville 3010 VIC
Australia
----------------------
SAC Help
Topic home: http://ds.iris.edu/message-center/topic/sac-help/ |
Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
----------------------
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Sanjay Singh Negi
Alternate Email: sasnegi85<at>gmail.com
Contact No.- +91-9536145596
-
Just multiply by -1.
On Oct 28, 2020, at 5:58 AM, Sanjay Singh Negi <sonoogeo<at>gmail.com> wrote:
[This email originated from outside of OSU. Use caution with links and attachments.]
Hi John,
I never thought about it, but logically it seems correct.
It means that in order to flip, I need to rotate the vertical component to 180 degrees.
Thanks,
Sanjay
On Wed, Oct 28, 2020 at 1:31 AM Nabelek, John (via IRIS) <sac-help-bounce<at>lists.ds.iris.edu> wrote:
Sanjay
To convert right-handed system into left-haded, you will need to flip the vertical component.
For a high-handed system, positive vertical points down.
-John
On Oct 27, 2020, at 5:11 AM, Geo . (via IRIS) <sac-help-bounce<at>lists.ds.iris.edu> wrote:
----------------------
[This email originated from outside of OSU. Use caution with links and attachments.]
Hello Sanjay,
Based on the SAC documentation, your description of components, and assuming that your
orientation correction is clockwise from north (+80?, how did you estimate this?), it seems that "rotate to -80 reverse" is correct.
"Reverse" indicates that H2 is pointing north and H1 is pointing east: the second component is lagging the first by 90°. Think of it as the reverse convention as, usually, H1 and H2 are pointing north and east respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS) <sac-help-bounce<at>lists.ds.iris.edu> wrote:
Hi Sac users,
I have OBS record that follows the right-handed system in which H2 component is 90 degree counter-clockwise of H1.
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation correction of 80 degrees has to be made. For this, logically -80/360-80 degree should be implemented to rotate it back to North-South. Would +80 degree be fine?
2. What exactly sac does on applying reverse at the end of rotate command?
Thanks in advance.
Regards
Sanjay
--
Januka Attanayake
Research Fellow | Earthquake Seismology
Homepage: https://sites.google.com/site/janukaattanayake
School of Earth Sciences | McCoy Bldg. 200
University of Melbourne | Parkville 3010 VIC
Australia
----------------------
SAC Help
Topic home: http://ds.iris.edu/message-center/topic/sac-help/ | Unsubscribe: sac-help-unsubscribe<at>lists.ds.iris.edu
Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/
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Topic home: http://ds.iris.edu/message-center/topic/sac-help/ | Unsubscribe: sac-help-unsubscribe<at>lists.ds.iris.edu
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Update subscription preferences at http://ds.iris.edu/account/profile/
--
Sanjay Singh Negi
Alternate Email: sasnegi85<at>gmail.com
Contact No.- +91-9536145596
-
Thank you for the correction.
Regards
Sanjay
On Wed, Oct 28, 2020, 22:53 Nabelek, John (via IRIS) <
sac-help-bounce<at>lists.ds.iris.edu> wrote:
Just multiply by -1.
On Oct 28, 2020, at 5:58 AM, Sanjay Singh Negi <sonoogeo<at>gmail.com>
wrote:
[This email originated from outside of OSU. Use caution with links and
attachments.]
Hi John,
to 180 degrees.
I never thought about it, but logically it seems correct.
It means that in order to flip, I need to rotate the vertical component
Thanks,
sac-help-bounce<at>lists.ds.iris.edu> wrote:
Sanjay
On Wed, Oct 28, 2020 at 1:31 AM Nabelek, John (via IRIS) <
Sanjay
the vertical component.
To convert right-handed system into left-haded, you will need to flip
For a high-handed system, positive vertical points down.
sac-help-bounce<at>lists.ds.iris.edu> wrote:
-John
On Oct 27, 2020, at 5:11 AM, Geo . (via IRIS) <
[This email originated from outside of OSU. Use caution with links and
Hello Sanjay,
Based on the SAC documentation, your description of components, and
orientation correction is clockwise from north (+80?, how did you
"Reverse" indicates that H2 is pointing north and H1 is pointing east:
reverse convention as, usually, H1 and H2 are pointing north and east
respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS) <
Hi Sac users,
I have OBS record that follows the right-handed
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation
degree should be implemented to rotate it back to North-South. Would +80
degree be fine?
2. What exactly sac does on applying reverse at the end of rotate
Thanks in advance.
Regards
Sanjay
--
Januka Attanayake
Research Fellow | Earthquake Seismology
Homepage: https://sites.google.com/site/janukaattanayake
School of Earth Sciences | McCoy Bldg. 200
University of Melbourne | Parkville 3010 VIC
Australia
----------------------
SAC Help
Topic home: http://ds.iris.edu/message-center/topic/sac-help/ |
Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
----------------------
Update subscription preferences at http://ds.iris.edu/account/profile/
SAC Help
Topic home: http://ds.iris.edu/message-center/topic/sac-help/ |
Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
----------------------
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--
Sanjay Singh Negi
Alternate Email: sasnegi85<at>gmail.com
Contact No.- +91-9536145596
SAC Help
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-
Sorry for the delay, but ...
If one simply flips the vertical, the header variable CMPINC will not be correct
for that component.
CMPINC is defined as Component incident angle (degrees from upward vertical)
To be complete one must change CMPINC for that component to 180 if one
multiplies it by -1.
While looking this up in the PDF manual, I found we had inadvertently left out
the SAC Data File Format in the PDF manual (it is there in the HTML version).
That will be fixed shortly.
Please let me know of any other problems in the PDF/HTML manuals.
Arthur
On 10/28/20 2:19 PM, sanjay Singh Negi (via IRIS) wrote:
Thank you for the correction.
Regards
Sanjay
On Wed, Oct 28, 2020, 22:53 Nabelek, John (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu <sac-help-bounce<at>lists.ds.iris.edu>>
wrote:
Just multiply by -1.
On Oct 28, 2020, at 5:58 AM, Sanjay Singh Negi <sonoogeo<at>gmail.com
<sonoogeo<at>gmail.com>> wrote:
[This email originated from outside of OSU. Use caution with links and
attachments.]
Hi John,
to 180 degrees.
I never thought about it, but logically it seems correct.
It means that in order to flip, I need to rotate the vertical component
Thanks,
<sac-help-bounce<at>lists.ds.iris.edu
Sanjay
On Wed, Oct 28, 2020 at 1:31 AM Nabelek, John (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu>> wrote:
Sanjay
the vertical component.
To convert right-handed system into left-haded, you will need to flip
For a high-handed system, positive vertical points down.
<sac-help-bounce<at>lists.ds.iris.edu
-John
On Oct 27, 2020, at 5:11 AM, Geo . (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu>> wrote:
[This email originated from outside of OSU. Use caution with links and
Hello Sanjay,
Based on the SAC documentation, your description of components, and
orientation correction is clockwise from north (+80?, how did you
"Reverse" indicates that H2 is pointing north and H1 is pointing east:
reverse convention as, usually, H1 and H2 are pointing north and east
respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu>> wrote:
Hi Sac users,
I have OBS record that follows the right-handed
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac 2018.128.01.00.45.420.X.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is correct or not?
Why I am confused about rotation is because of two following reasons:
1: To get true north-south rotation for an OBS record the orientation
degree should be implemented to rotate it back to North-South. Would +80
degree be fine?
2. What exactly sac does on applying reverse at the end of rotate command?
Thanks in advance.
Regards
Sanjay
-
Dear Prof. Snoke,
Thank you for your email. The CMPINC will be
taken into account.
I will be glad to contribute and update on any problem related to SAC.
With warm regards,
Sanjay
On Thu, Dec 3, 2020 at 11:46 PM Arthur Snoke (via IRIS) <
sac-help-bounce<at>lists.ds.iris.edu> wrote:
Sorry for the delay, but ...
--
If one simply flips the vertical, the header variable CMPINC will not be
correct
for that component.
CMPINC is defined as Component incident angle (degrees from upward
vertical)
To be complete one must change CMPINC for that component to 180 if one
multiplies it by -1.
While looking this up in the PDF manual, I found we had inadvertently left
out
the SAC Data File Format in the PDF manual (it is there in the HTML
version).
That will be fixed shortly.
Please let me know of any other problems in the PDF/HTML manuals.
Arthur
On 10/28/20 2:19 PM, sanjay Singh Negi (via IRIS) wrote:
Thank you for the correction.
sac-help-bounce<at>lists.ds.iris.edu>>
Regards
Sanjay
On Wed, Oct 28, 2020, 22:53 Nabelek, John (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu <mailto:
wrote:
and
Just multiply by -1.
On Oct 28, 2020, at 5:58 AM, Sanjay Singh Negi <sonoogeo<at>gmail.com
<sonoogeo<at>gmail.com>> wrote:
[This email originated from outside of OSU. Use caution with links
attachments.]
component
Hi John,
I never thought about it, but logically it seems correct.
It means that in order to flip, I need to rotate the vertical
to 180 degrees.
flip
Thanks,
<sac-help-bounce<at>lists.ds.iris.edu
Sanjay
On Wed, Oct 28, 2020 at 1:31 AM Nabelek, John (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu>> wrote:
Sanjay
To convert right-handed system into left-haded, you will need to
the vertical component.
links and
For a high-handed system, positive vertical points down.
<sac-help-bounce<at>lists.ds.iris.edu
-John
On Oct 27, 2020, at 5:11 AM, Geo . (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu>> wrote:
[This email originated from outside of OSU. Use caution with
attachments.]
and
Hello Sanjay,
Based on the SAC documentation, your description of components,
assuming that your
east:
orientation correction is clockwise from north (+80?, how did you
"Reverse" indicates that H2 is pointing north and H1 is pointing
the second component is lagging the first by 90°. Think of it as the
right-handed
reverse convention as, usually, H1 and H2 are pointing north and east
respectively.
http://www.adc1.iris.edu/files/sac-manual/commands/rotate.html
Januka
On Tuesday, 27 October 2020, sanjay Singh Negi (via IRIS)
<sac-help-bounce<at>lists.ds.iris.edu>> wrote:
Hi Sac users,
I have OBS record that follows the
system in which H2 component is 90 degree counter-clockwise of H1.
2018.128.01.00.45.420.X.sac
Horizontal component data file are as following:
2018.128.01.00.45.420.X.sac ---> East component
2018.128.01.00.45.420.Y.sac ----> North component
2018.128.01.00.45.420.Z.sac ----> Vertical component
The orientation correction angle is 80 degree.
For rotation, I use the following scheme:
sac>> read 2018.128.01.00.45.420.Y.sac
sac>> rotate to 80 reverse
Could you please comment on whether the command I give is
Why I am confused about rotation is because of two following
1: To get true north-south rotation for an OBS record the
correction of 80 degrees has to be made. For this, logically
-80/360-80
degree should be implemented to rotate it back to North-South. Would
+80
degree be fine?
rotate command?
2. What exactly sac does on applying reverse at the end of
Thanks in advance.
Regards
Sanjay
SAC Help
Topic home: http://ds.iris.edu/message-center/topic/sac-help/ |
Unsubscribe: sac-help-unsubscribe<at>lists.ds.iris.edu
Sent from the IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/
Sanjay Singh Negi
Alternate Email: sasnegi85<at>gmail.com
Contact No.- +91-9536145596
-
-
-
-
-
-